1. Field of the Invention
This invention relates to a system and a method for cylindrically forming and quenching glass sheets.
2. Background Art
Glass sheet press bending has previously been performed with a prebending that takes place after the glass sheets exit a furnace but before transfer to a press bending station where the press bending takes place. See, for example, U.S. Pat. Nos. 5,368,625 Mizusugi, 5,545,245 Mizusugi and 5,735,922 Woodward et al., which disclose a roll bending station located between the exit end of the associated furnace and a press bending station. The roll bending station disclosed by the above patents has horizontal rolls and laterally spaced sets of inclined bending rolls located downstream from the furnace with the inclined rolls provided in sets having progressively increasing inclination along the direction of conveyance to form each heated glass sheet during conveyance over the inclined rolls. See also PCT international application publication nos.: WO 02/102726 Bennett; WO 02/102727 Bennett et al.; and WO 03/010100 Bennett et al., which disclose a roll bending station located within the furnace adjacent its exit end. The roll bending station of these PCT applications has horizontal rolls and laterally spaced sets of inclined bending rolls located within the furnace adjacent its exit end with the inclined rolls provided in sets having progressively increasing inclination along the direction of conveyance to form each heated glass sheet during conveyance over the inclined rolls, and a press bending station located downstream from the furnace receives the formed glass sheet from the furnace for the press bending. Press bending of glass sheets is conventionally performed between a pair of full surface molds or between a full surface mold and a peripheral ring to provide the glass sheet bending.
As disclosed by French Patent 2221409 of inventor Maurice Nedelec, heated glass sheets have also previously been bent by conveyor rolls that are supported and rotatively driven outside of a furnace heating chamber with ends projecting inwardly into the furnace initially in a horizontal orientation. All of the rolls are subsequently simultaneously tilted to form the heated glass sheet within the heated chamber.